$\dfrac{6}{2} - \dfrac{4}{8} = {?}$
Solution: $ = {\dfrac{6 \times 4}{2 \times 4}} - {\dfrac{4 \times 1}{8 \times 1}} $ $ = {\dfrac{24}{8}} - {\dfrac{4}{8}} $ $ = \dfrac{{24} - {4}}{8} $ $ = \dfrac{20}{8}$